The present invention relates to an apparatus and method for preventing growth of microbia propagating themselves on an internal wall of a carrier tube for carrying beer and other beverages, or for removing the microbia.
There has been a beverage supply apparatus comprising, as a supply source, a barrel referred to as a keg which has beer and alcoholic beverages in draft form put therein, the supply source being coupled to an outlet such as a draft cock through a carrier tube (a pipe or duct). Such an apparatus has often been utilized in a hotel or associated industries. For example, an outlet is attached to a bar of the hotel and the keg is provided on the outside of the bar. Beverages such as beer and the like are carried from the keg to the outlet through the carrier tube. Microbia (including bacteria and yeast) easily propagate themselves on the inside of the carrier tube through which the beverages pass. Consequently, it is necessary to periodically perform cleaning by usually causing a flushing fluid or the like to pass into the carrier tube. There has also been proposed an apparatus for preventing the growth of the microbia or removing the microbia by an electromagnetic field in place of the periodic cleaning (see Japanese Laid-Open Patent Publication No. Hei 8-501520, for example). This apparatus has a structure in which a coil is wound around a partial section of a pipe or duct and an electric signal is sent to the coil, thereby preventing growth of microbia in the pipe or duct or removing the microbia.
However, the applicant has investigated effects of the conventional apparatus by experiments. As a result, it has found that the electromagnetic field produces no or less effect of prevention of the growth of the microbia or removal of the microbia.
Furthermore, the following is apparent. Even if the electromagnetic field produces the effect of the prevention of the growth of the microbia or the removal of the microbia, the effect can be obtained only in the proximity of a portion where the coil is wound but cannot be obtained over a whole carrier tube for coupling a keg to an outlet. In addition, it has been found that an audio electronic signal is very effective in the prevention of the growth of the microbia or the removal of the microbia in place of the electromagnetic field.
It is an object of the present invention to provide an apparatus and method for preventing growth of a biofilm of microbia (including bacteria and yeast) which propagate themselves on an internal wall of a carrier tube (pipe or duct) for carrying beer, in particular, barreled beer (draft beer) and other beverages or removing the microbia without requiring periodic use of chemicals which are not preferable environmentally.
In order to solve the above-mentioned problems, the present invention provides an apparatus for preventing growth of microbia propagating themselves on an internal wall of a carrier tube for carrying beverages or for removing the microbia, comprising electric signal generating means for generating an electric signal including an audio frequency component, a transponder including a coil and a case for housing the coil, and means for attaching the transponder to an external wall of the carrier tube, wherein the electric signal is applied to the coil so that an audio electronic signal to be sent through the carrier tube can be generated. Furthermore, the present invention provides a method for preventing growth of microbia propagating themselves on an internal wall of a carrier tube for carrying beverages or for removing the microbia, comprising the steps of generating an electric signal including an audio frequency component, attaching a transponder including a coil and a case for housing the coil to an external wall of the carrier tube, and applying the electric signal to the coil, thereby generating an audio electronic signal to be sent through the carrier tube. According to the apparatus and method, the growth of the microbia can be prevented by the audio electronic signal. The audio electronic signal is sent through the carrier tube so that an effect of the prevention of the growth of the microbia ranges widely in the carrier tube.
In particular, if the electric signal frequency-modulates around a predetermined frequency and the frequency modulation further causes the audio electronic signal to include a harmonics component, the above-mentioned effect can be made remarkable.
It is preferable that the predetermined frequency should be between 1500 Hz and 2500 Hz.
If a face of the transponder which comes in contact with the carrier tube has a concave shape whose section is circular, a state of attachment of the transponder to the carrier tube can be stabilized.
It is preferable that the transponder should be attached near an end of the carrier tube. The reason is that this portion causes the microbia to be increased most easily.
Although carrier tubes for all beverages can be considered as the above-mentioned carrier tube, a carrier tube for carrying beer can be used, for example.